"During the build-up to the Cold War, the U.S. government called upon hundreds of factories and research centers to help develop nuclear weapons and other forms of atomic energy. At many sites, this work left behind residual radioactive contamination requiring government cleanups, some of which are still going on."

"The Department of Energy says it has protected the public health, and studies about radiation harm aren’t definitive. But with the government's own records about many of the sites unclear, the Journal has compiled a database that draws on thousands of public records and other sources to trace this historic atomic development effort and its consequences."